Please help with alpha matte

Hi everyone! I don't know if this is the right place to search for help. If it's not, I ask moderators to move my thread to the right place.

I would like to submit my first video with luma matte. But I am not sure how to do it, so I'm asking for help.

My video is 1280x720, and it's made in Particle Illusion 3. I exported it uncompressed.
I also exported uncompressed black and white luma mate.

But now, I am not sure how to submit it? Do I have to join videos to become one video, or I can submit separate videos somehow?
Also, I usually convert my videos to 85% quality .mov files.
Can I do the same with this video? Is compressing going to affect quality of matte? Do I maybe have to submit it uncompressed?

Thank you in advance!
Ivan

There is something in particleIllusion that hasn't already been submitted 20 times? Wow...

And yes, you need to add the luma matte to the end of your regular clip to make it all one video clip.

And submitting it with the normal PhotoJPEG is fine.

thank you!
So, if I make 85% quality photoJPEG video out of full uncompressed video exported from PI3, luma matte will still be useful? I mean, compressed luma matte still precisely covers original video?
... You know what I mean? :)

Is there any other small application that can join two videos but to remain everything to be as source videos (codec etc..)?

Yes, although you might want to do it at 90%. And have you tried http://www.squared5.com/?

Oh, I'm using MPEG Streamclip :)
Thank's again!
Ivan